1. Technical Field
The invention relates to a gasket for use in detachably connecting two similar coupling members on the ends of air brake hoses for railroad cars to form an airtight connection. More particularly, the invention relates to an improved air brake hose coupling member having improved sealing means that provide better alignment and sealing during coupling with a similar member on an adjacent railroad car. Specifically, the invention relates to an improved gasket incorporating a ramped entrance angle and a wide sealing surface for providing better alignment and sealing during coupling with another similar member.
2. Background Information
Railroad cars having pneumatic brake systems use flexible air hoses which extend the length of the train by spanning between separate yet adjacent railroad cars. Typically, at least one flexible hose extends from the front to the back of a railroad car with a fluid connection branching off to the emergency brake system midway therebetween. A coupling member is attached to each end of each flexible hose for detachably connecting the hose sections of adjacent cars together when individual railroad cars are joined to form a unit train. These coupling members whether connected to another or not, are suspended from the end of the car and hang a short distance above the ground or railroad tracks. Overall, these couplings are designed and manufactured to meet the requirements of the Association of American Railroads and are generally similar, so as to be compatible and interchangeable with those of other manufacturers.
As is well known in the art, these couplings are joined together by pulling the hoses from adjacent cars upward, pushing the sealing gaskets on the coupling members at the end of each hose into aligned and abutting relationship, and then rotating the coupling members downward which interengages mating flanges and lugs extending from the coupling members. If properly performed, this results in a sealed fluid passage between air hoses on adjacent railroad cars whereby the air pressure in the hose lines maintains the brakes of all of the individual cars in an "off" position. Any significant reduction in air pressure within these hose lines actuates the brakes in all of the individual cars to an "on" or braking position. If the train were to derail, or cars were to accidentally separate, or if for any other reason the air was to leak resulting in decreased pressure then all of the cars go into this braking position. Thus, accidental separation of the coupling between two sections of air hose will apply the emergency car brakes, resulting in sudden stopping of a train with the subsequent delay, inconvenience and expense as well as chance of accidents, and therefor any accidental disconnection of the couplings needs to be avoided.
Clearly, each connection of adjacent coupling members is critical since only one leak stops the entire train. However in operation, the couplings are often difficult to properly align. Improper alignment often either results in an ineffective (leaky) seal or no seal at all. However, in many cases the tolerances in the couplings allow the downward rotational locking motion anyway even though the coupling members are misaligned. When two coupling members are misaligned yet locked, the connection may or may not seal. When sealing does not occur, the brakes do not release thereby prohibiting movement of the train. These locked brakes force a brakeman to inspect the connections to find the unsealed connection, which once found can then be relocked in hopefully an aligned manner. This inspection and relocking is a time consuming event. In addition, the brakeman may find that the seal has been damaged. In this case, the seal must also be replaced prior to relocking.
An even more drastic scenario is where the misaligned coupling members improperly seal. In this case, the improper seal may hold the pneumatic pressure for awhile or until sufficiently jarred such as during standard operation. If the seal is not capable of holding standard operational pressures of 60 to 90 p.s.i., and the seal fails during operation then undesirable emergency braking occurs which stops the train. The failed coupling must be found, fixed or replaced, and recoupled before the train can move. This is again a time consuming event.
In addition, even when alignment is proper, the sealing surfaces of the gasket must be able to withstand upwards of 90 p.s.i. during operation. As is well known in the art, the seal must be sufficient to hold this pressure while not inhibiting the coupling member's ability to separate along the hose axis during a standard disconnect. Current seal designs sometimes fail in holding the pneumatic pressure resulting in these seals leaking either slowly or rapidly which releases the pneumatic pressure which causes emergency brake activation.
Thus, a current problem exists surrounding alignment of the gaskets of two adjacent coupling members which only if aligned seal properly and allow for proper connection and separation. In sum, it has been found that standard prior art gaskets such as that shown in FIG. 8 are not conducive to proper alignment and engagement as is required for necessary sealing of coupled air brake hose coupling members at the standard air brake pressures of between 60 p.s.i. and 90 p.s.i. Overall, improper alignment of the gaskets causes poor or ineffective sealing due to gasket misalignment which results in a higher likelihood of uncoupling of air hose couplings due to misalignment of the gaskets, or poor sealing both of which result in too little pull apart resistance whereby said lack of separation resistance causes the air hose couplings to fall apart which immediately throws the entire train into an emergency brake application. All of this results in added costs and time, both of which are undesirable.
Thus, a need has existed for an improved air brake hose coupling member which enables rapid connection of hose sections in the heretofore usual manner without additional manipulations being required, which does not affect the usual rotational connection, separation and operation of such coupling members, and which does not affect the usual axial separation and operation of such coupling members while preventing or considerably reducing premature uncoupling of the attached members in an axial manner due to improper gasket alignment and/or poor sealing.